Heat and pressure sensitive valve



Feb. 23, 1965 E. P. wHlTLow HEAT AND PRESSURE SENSITIVE VALVE Filed Jan. 28, 1965 ATTYS.

United States Patent O 3,170,631 HEAT AND PRESSURE SENSITIVE VALVE Eugene P. Whitlow, St. Joseph, Mich., assignor to American Gas Association, New York, N.Y., a corporation of New York Filed Jan. 28, 1963, Ser. No. 254,342 2 Claims. (Cl. 236-92) The present invention relates generally to gas valves and more particularly to heat and pressure sensitive gas valves.

Although the invention is suitable for a variety of applications to release a gas when predetermined temperature and pressure conditions occur, the value is especially Well adapted for venting fixed gases from absorption type refrigeration systems. Accordingly, the embodiment described herein is presented in such a setting for purposes of illustration and not as a limitation on the scope of application of invention.

Absorption refrigeration systems include such elements as evaporators, absorbers, heat exchangers and condensers, as wellas substantial lengths of conduit. The pressure and temperature of the refrigerant and absorbent mediums vary markedly in traveling through the several regions of the sealed systems, the pressure being at certain stages below atmospheric pressure. Non-condensible or fixed gases develop in the systems, primarily from corrosion of metal huid-containing elements and leakage in the low pressure regions. Since fixed gases are apt to impair the operation of the condsenser and absorber stages, they must be eliminated to maintain an efficient absorption cycle. Complicated devices for trapping lixed gases for periodic removal have previously been used, but

f a truly dependable, leak-tight and inexpensive vent Value such as that presently described has not heretofore been developed.

Modern absorption systems generally include a pump `which causes regions of the system to be above atmospheric pressure, and it is for this type of system that the -present device aifords a means for continuously accumulating and venting fixed gases. The present valve is particularly Well adapted for venting gases from the absorp- 'tion system disclosed in the co-pending application Serial Number 229,514, iiled August 20, 1962, assigned to the present assignee. Fixed gases in that system accumulate lin the steam space of the second effect generator from which they may be continuously and automatically exhausted to the atmosphere by means of the applicants valve.

Accordingly, it is an object of the invention to provide a simple, dependable and leak-tight heat and pressure sensitive gas valve which will automatically open to provide a passage or venting of gas only upon the occurrence of predetermined temperature and pressure conditionsof'` the gas.

An additional object of the invention is to provide a heat and pressure sensitive valve as described having a iirst'temperature sensitive element and a second pressure sensitive element, said pressure sensitive element acting as a check valve and permitting gas flow in one direction only. n A further object is to provide a valve as described characterized by a simplicity of design and having a single moving part, thus minimizing manufacturing costs and requiring little, if any, maintenance.

The present invention, in realizing these and other objects, includes briefly a vertical tube, Vsealed at its upper end, having a vertically extending bimetallic strip fastened Y therewithin by one end to the tube wall. Opposed from 2, and 3.

the free end of the strip is a small orice in the tube wall 3,179,631 Patented Feb. 23, 1965 disposed so as to be closed by the bimetallic strip upon lateral movement thereof,

A larger vertical outer tube surrounds and extends above the bimetallicstrip-containing tube and is sealed to the smaller tube below the orifice. Mounted in the upper end of the larger tube is a check valve comprising a sintered glass disc tted within the tube covered by a thin layer of mercury. The valve functions to Vent gases only when the gases are sufciently cool to contract the bimetallic strip away from the orifice and when the pressure in the valve is greater than the atmospheric or other pressure above the mercury-glass check valve.

Additional objects and advantages of the invention will be more readily apparent from the following detailed description of an embodiment thereof when taken together with the accompanying drawings, in which:

FIG. 1 is an elevational sectional view of a valve embodying the invention showing the temperature sensitive bi-metallic elements in the open or vent position;

FIG. 2 is an enlarged elevational sectional View of the upper end of the bimetallic elements showing their normal open position with respect to the opposed orifice and indicating in broken lines the closed position of the elements; l

FIG. 3 is a sectional View taken along lines 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along lines 4-4 of FIG. l;

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 4; and

FIG. 6 is a perspective View isolating the upper portion of the bimetallic elements and the opposed orifice with which it coacts to close the valve at elevated temperatures.

Referring to the drawings, FIG. 1 shows a heat and temperature sensitive valve generally designated 16 connected with a vessel 12 which for purposes of describing the operation of the valve is considered to be the steam .space of the second eifect generator of the absorption refrigeration system disclosed in the above-mentioned c0- pending application. The Valve includes a vertical tubular valve body 14, which is joined to a horizontal tube 16 to provide a passage from the Vessel 12 into the valve. The connection 18 of the valve body 14 to the tube 16 and the entrance 26 of the tube 16 through the vessel 12 are sealed such as by welding or soldering.

The upper end 22 of the valve body 14 is capped in any suitable manner to provide a gas-tight seal. Bimetallic elements 24 are vertically positioned within valve body 14, attached at the lower end thereof to the body wall by bolt 26 and nut 28. The bolt is soldered to the Valve body wall to provide a rigid, sealed mounting. The bimetallic elements extend' nearly the full vertical height of the valve body, terminating in an upper end 30 just short ofthe body end 22. l

As Vshown in FIG. l and more clearly in FIGS. 2, 3 and 6,A a plug 32 is mounted on one side of upper end 3,0 of elements 24 consisting of a short ring-shaped tube 34 yin which is secured resilient disc 36 of soft rubber or similar material. `Cylindrical insert 38 is mounted in the valve body wall opposed from the plug 32, and. includes a concentric inwardly projecting annular neck portion 4t). The insert is concentrically bored to provide a small orifice 44 therethrough. The bimetallic elements, plug, and insert in effect comprises a temperature sensitive valve which is shown in the open position of FIGS. 1,

A tubular stack 46, substantially larger in diameter than the valve body 14 is secured to. the valve body below the is glass chimney 48, the lower portion of which is prefgases to -a suitable checkyalve.

erably -of the same diameter as the stack to facilitate a sealed connection therebetween. Rubber tubing 50 bonded to the stack and chimney with suitable adhesive provides an air-'tightcoupling y The chimney 48 is reduced in cross-section at 52,.pro ducing a relatively narrow upper chimney passageSl. Within this passage is located check valve 56 consisting of a sintered glass disc d fitted within the chimney, the upper `surface of which is completely covered by a kdrop of mercury such `that a mercury layer 60 extends across the passage.

In operation, the valve is attached as .indicated to a vesselV '12 from which it is desired to vent gases under certain predetermined temperature and pressure conditions. Assuming, as-suggested above, that the vessel I2 represents the second effect generator of the forernentioned absorption refrigeration system, the tube I6 and valve vbody 14 open int-o a chamber containing steam at a pressure above atmospheric from which it is desired to remove non-condensible gases. The steam enters the Lvalve `body 14 and heats the enclosed bimetallic elements 24, causing the elements to move laterally as indicated in the broken lines of FIG. 21such that the plug 32. engages the insertSS, closing thetemperature-sensitive valve, the neck 40 being biased against resilient disc 36 thus sealing the orifice 44.

Since the valve body is outside `of the second eectgenerator, the surrounding air provides a cooling effect whichVr .condenses the steam within the valve body. As the condensate flows back into the vessel 12, more steam enters from the vessel to replace that which has been condensed'. This cycle establishes a ow of steam into the valveibody .where it is condensed, the condensate fiowing back into "the vessel 12 and converted into steam. The bimetallic Ywhich are carried-into the valve body by the steam flow will remain in the valve body, accumulating'in the upper regions thereof. The accumulation of'xed gases shields 'the upper portion of the bimetallic elements from steam and decreases the amount of steam passing into the valve body, "the temperature of the valve and the bimetallic elements dropping correspondingly. When the temperature yof the elements is lowered to a predetermined'level,

the elements-move laterally away from the insert 38, open- 'ingthe orifice 44, and permitting the fixed gases to flow into the stack 46, chimney 48, and through the check valve 56. The gases, being at a pressure above atmospheric, pass through the sintered glass disc 5S and through the mercury layer 60. As the fixed gases vacate the -valve body, steam immediately enters and, contacting the -sensitive bimetallic elements, laterally activates the ele- -ments,`closingfthe orifice 44 before steam can pass therethrough. Steam resumes its flow intothe valve body and 'fixed-gases are again accumulated until a suiiicient volume lis present to cool the bimetallic elements and again open ithe orifice.

In the event that pressure inside the valve body and stack should be below atmospheric pressure when the tem-l perature sensitive valve opens, the check Valve prevents outside airfrom entering the system, the mercury closing -the pores of `the sintered glass.

Thebimetallic elements should be sufficiently sensitive *to close the `orifice before steam4 advances into the upper region ofthe valve body even though all fixed gases have not been vented. This assures against the loss of refrigerantfrom the sealed absorption system.

The connected stack and chimney constitute a sealed gas conduit and the-structure of this conduit may be varied as desired toprovidea sealed passage channelling Y The simplicity of the valve and the absence of moving parts other than the bimetallic elements, provide a particularly dependable vent valve. The mercury-sintered glass check valve has a high tolerance f-or dustV and, dirt which vare a prime cause of leakage in other types of check valves.

yeffected byV those skilled in the art without departing from the spirit and the scope of the inventionas defined in and limited solely by the appended claims.

I claim: l j Y l. Avalve for venting gases upon occurrence of predetermined 4temperature and pressure v conditions therein comprising a vertical sealed valve body, means for introducing a'gas into said valve body, temperature-sensitive .bimetallic elements vertically disposed within said valve body, a free end of said elements adapted lfor movement in response to temperature variations of a gas within said valve body, an orifice in the side wall of saidvalve body juxtaposed from said free end of said elements and adapted to receive said free end to provide a sealing engagement -therebetween upon thermal expansion Vof said elements,

a vertical stack surrounding said valve'body secured theretoin sealing .relation at a point below said orifice, a chimney joined to said stack and a check lvalve 'in said chimney, said check valve comprising a porous horizontal disc sealed within said chimney and a layer of mercury covering said disc, a flow of gas passing through said valve only when the gas is at a temperature affecting said bimetallic elements so as to open said orice, and when the gas is at a'pressure suicient for flow through said check valve.

2. In combination,A a .sealed `refrigeration system, and

a valvefor automatically venting non-condensible gasesL from said system, said valve comprising a vertically extending sealed tubular valve body, means providing a luid connection between the lower end'of said valve body and a region of the refrigeration system, a temperature-sensitive bimetallic element disposed longitudinally within .said valve body, the lower end of said bimetallic elementbeing secured inthe lower end of-said v valve body spaced from the walls thereof, the upper end of said bimetallic element being free for transverse movement within said valve body in response to temperature variations of a gas within said valve body, an orifice in the side of said valve body juxtaposed from the free end of said' bimetallic element and adapted tok receive said free end in sealing engagement upon thermal expansion `of said element, a vertical tubular stack coaxial with and surrounding an upper portion of said valve body in Vspaced relation'therefrom,y said stack being `secured thereto in sealing relation at a Vpoint below said orificeya vertical chimney connected with said stack, and a'check valve in said chimney, said check valve comprising a porous horizontal disc sealed within said chimney and la layer of Inercury covering said disc, said valve automatically venting non-condensible gases from the refrigeration system when the gases are'at a suiciently cool temperature to open said orifice and at a pressure suflicient for ow through said check valve.

V9/05 Roys 236-59 X 3/ 19 Boyd.

E d UNITED STATES PATENTS Chadeayne 236-66 Stadehofer 236-66 X Gildersleeve 137--251 Bond 137-251 Matthews 236--50 6 FOREIGN PATENTS 919,512 10/54 Germany.

EDWARD I. MICHAEL, Primary Examiner.

5 ALDEN D. STEWART, Examiner. 

1. A VALVE FOR VENTING GASES UPON OCCURRENCE OF PREDETERMINED TEMPERATURE AND PRESSURE CONDITIONS THEREIN COMPRISING A VERTICAL SEALED VALVE BODY, MEANS FOR INTRODUCING A GAS INTO SAID VALVE BODY, TEMPERATURE-SENSITIVE BIMETALLIC ELEMENTS VERTICALLY DISPOSED WITHIN SAID VALVE BODY, A FREE END OF SAID ELEMENTS ADAPTED FOR MOVEMENT IN RESPONSE TO TEMPERATURE VARIATIONS OF A GAS WITHIN SAID VALVE BODY, AN ORIFICE IN THE SIDE WALL OF SAID VALVE BODY JUXTAPOSED FROM SAID FREE END OF SAID ELEMENTS AND ADAPTED TO RECEIVE SAID FREE END TO PROVIDE A SEALING ENGAGEMENT THEREBETWEEN UPON THERMAL EXPANSION OF SAID ELEMENTS, A VERTICAL STACK SURROUNDING SAID VALVE BODY SECURED THERETO IN SEALING RELATION AT A POINT BELOW SAID ORIFICE, A CHIMNEY JOINED TO SAID STACK AND A CHECK VALVE IN SAID CHIMNEY, SAID CHECK VALVE COMPRISING A POROUS HORIZONTAL DISC SEALED WITHIN SAID CHIMNEY AND A LAYER OF MERCURY COVERTING SAID DISC, A FLOW OF GAS PASSING THROUGH SAID VALVE ONLY WHEN THE GAS IS AT A TEMPERATURE AFFECTING SID BIMETALLIC ELEMENTS SO AS TO OPEN SAID ORIFICE, AND WHEN THE GAS IS AT A PRESSURE SUFFICIENT FOR FLOW THROUGH SAID CHECK VALVE. 